Efficacy of Biometry Using Swept-source Optical Coherence Tomography for Posterior Chamber Phakic Intraocular Lens Implantation

Purpose@#The proper implantable collamer lens (ICL) size affects ICL stability. This study compared device efficacy using white-to-white diameter (WTW) measurements with Orbscan II and IOL Master 700. @*Methods@#We retrospectively studied 90 eyes (45 patients) who underwent toric ICL implantation from January 2019 to February 2020 and were followed for 1 year. The correlation between WTW and anterior chamber depth (ACD) for each measuring device was analyzed. @*Results@#The mean WTW measured by IOL Master 700 and Orbscan II was 12.2 ± 0.3 and 11.6 ± 0.3 mm, respectively, while the mean ACD was 3.28 ± 0.16 and 3.20 ± 0.15 mm. The WTW and ACD measured with IOL Master 700 averaged 0.57 ± 0.12 and 0.08 ± 0.04 mm larger than with Orbscan II. The differences were significant and the regression analysis had high correlations (R2 = 0.875 and R2 = 0.913, respectively; both p < 0.001). @*Conclusions@#WTW measured by the IOL Master 700 can be used as a reference either alone or together with the Orbscan II value to determine ICL size.

Short-term Comparison of Refractive Errors between Two Different Age Groups after LASEK for Moderate Myopia

Purpose@#To investigate the safety of laser epithelial keratomileusis (LASEK) by drawing a comparison between two groups divided according to age (18-19 vs. 20-21 years old). @*Methods@#The study was conducted as a retrospective analysis including 339 patients (678 eyes) who underwent LASEK between January 2017 and April 2020. Patients were divided by age group, group I (18-19 years old) and group II (20-21 years old). The objectives of the study included determination of visual acuity and refractive errors before and at 1, 3, and 6 months after the procedure. @*Results@#The preoperative mean spherical equivalents (SEs) were -4.73 ± 0.88 diopters (D) in group I and -4.58 ± 0.87 D in group II (p = 0.34). At 1 month postoperatively, mean SEs were 0.32 ± 0.46 D in group I and 0.26 ± 0.59 D in group II (p = 0.18). At 3 months postoperatively, the mean SEs were 0.30 ± 0.47 D in group I and 0.28 ± 0.50 D in group II (p = 0.67). At 6 months postoperatively, the mean SEs were 0.15 ± 0.47 D in group I and 0.14 ± 0.50 D in group II (p = 0.89). There were no significant differences in postoperative best corrected visual acuity between group I and group II at 1, 3, or 6 months (p = 0.20, p = 0.13, and p = 0.11, respectively). @*Conclusions@#There were no significant differences in postoperative mean SE or safety of LASEK between moderate myopia patients 18-19 years old and those 20-21 years old.

Intraocular Lens Power Calculation Using Shammas-PL Formula after Laser In-situ Keratomileusis

Purpose@#To calculate the intraocular lens (IOL) power using the Shammas-PL formula after laser in-situ keratomileusis (LASIK). @*Methods@#Forty-one eyes of 29 patients that had undergone cataract surgery from September 2018 to September 2019 after LASIK were enrolled in this study. A preoperative AL-Scan® (Nidek Co., Gamagori, Japan) was used to measure the axial length, anterior chamber depth, and corneal curvature. An IOL power calculation was performed using the Shammas-PL (post LASIK) formula. Mean absolute error (MAE) and mean arithmetic error (MARE) were calculated using preoperative manifest refraction and postoperative manifest refraction. @*Results@#Of the 41 eyes, 15 eyes (36.6%) were relatively hyperopic-shifted after surgery compared to the predicted refractive error before surgery, 25 eyes (61%) showed a relative myopic shift, and one eye (2.4%) showed no change with respect to the previous refractive predicted error. Refractive errors before cataract surgery were not related to myopic, emmetropic, or hyperopic shifting after surgery (p > 0.05). @*Conclusions@#When cataract surgery using the Shammas-PL formula was performed after LASIK, myopic shifting was more common than hyperopic shifting. The MAE was greater in myopic-shifted cases than that of hyperopic-shifted cases. Thus, it is better to determine IOL power toward the hyperopic side than the target refractive prediction.

Clinical Significance of Tear Film Osmolarity in Patients with Mild Dry Eye Syndrome

Purpose@#To seek Pearson correlations of tear film osmolarity measured by the I-PEN® (I-MED Pharma Inc., Dollard-des-Ormeaux, Canada) with Schirmer test result, tear break-up time, and Ocular Surface Disease Index score in patients with mild dry eye syndrome. @*Methods@#Patients with mild dry eye syndrome were divided into two groups according to Ocular Staining Score: group 1 (50 patients; 67 eyes) and group 2 (59 patients; 91 eyes), 90 patients and 158 eyes in total. The above mentioned correlations were derived. @*Results@#No significant correlations were observed between tear film osmolarity and Schirmer test result (r < -0.01, p = 0.97), tear break-up time (r = 0.05, p = 0.54), or Ocular Surface Disease Index score (r = 0.03, p = 0.76). When the two groups were compared, the Ocular Surface Disease Index score significantly differed between groups (p < 0.01), whereas the Schirmer test result (p = 0.31), tear break-up time (p = 0.11), and tear film osmolarity (p = 0.12) did not. @*Conclusions@#No significant correlations were found between tear film osmolarity and other dry eye indicators in patients with mild dry eye syndrome. The diagnostic utility of tear film osmolarity in patients with moderate dry eye syndrome is should be evaluated.

Clinical Significance of Tear Film Osmolarity in Patients with Mild Dry Eye Syndrome

Purpose@#To seek Pearson correlations of tear film osmolarity measured by the I-PEN® (I-MED Pharma Inc., Dollard-des-Ormeaux, Canada) with Schirmer test result, tear break-up time, and Ocular Surface Disease Index score in patients with mild dry eye syndrome. @*Methods@#Patients with mild dry eye syndrome were divided into two groups according to Ocular Staining Score: group 1 (50 patients; 67 eyes) and group 2 (59 patients; 91 eyes), 90 patients and 158 eyes in total. The above mentioned correlations were derived. @*Results@#No significant correlations were observed between tear film osmolarity and Schirmer test result (r < -0.01, p = 0.97), tear break-up time (r = 0.05, p = 0.54), or Ocular Surface Disease Index score (r = 0.03, p = 0.76). When the two groups were compared, the Ocular Surface Disease Index score significantly differed between groups (p < 0.01), whereas the Schirmer test result (p = 0.31), tear break-up time (p = 0.11), and tear film osmolarity (p = 0.12) did not. @*Conclusions@#No significant correlations were found between tear film osmolarity and other dry eye indicators in patients with mild dry eye syndrome. The diagnostic utility of tear film osmolarity in patients with moderate dry eye syndrome is should be evaluated.

Central Toxic Keratopathy after Femtosecond Laser in-situ Keratomileusis

Purpose@#To report a case of central toxic keratopathy after femtosecond laser in-situ keratomileusis (LASIK).Case summary: A 26-year-old male developed diffuse lamellar keratitis bilaterally on day 2 after femtosecond LASIK. He was applying topical steroid frequently, while also using topical antibiotics. On day 6 after LASIK, slit-lamp biomicroscopy showed a thick central corneal opacity on the right eye so a flap irrigation was performed. He was then treated with systemic methylprednisolone. A corneal epithelial crack and stromal striae were noted by slit-lamp biomicroscopy on postoperative day 10. Four weeks after LASIK, the refractive error was +4.25 Dsph = -1.25 Dcyl Axis 80°. He was treated with topical steroid, topical antibiotics, and oral doxycycline until eight weeks after LASIK. Eight weeks after LASIK, the patient was observed without treatment. The central corneal thickness recovered from 488 μm at eight weeks to 540 μm, and the refractive error was +1.25 Dsph = -0.75 Dcyl Axis 85° at postoperative 72 weeks. The central corneal opacity also recovered. @*Conclusions@#Because femtosecond LASIK may result in a combination of diffuse lamellar keratitis and central toxic keratopathy, the clinical characteristics and natural course of both diseases should be understood and timely treatment should be available.

Comparison of Perioperative Contrast Sensitivity between Laser in situ Keratomileusis and Small-incision Lenticule Extraction

Purpose@#To compare contrast sensitivity before and after surgery in patients who underwent laser in situ keratomileusis (LASIK)and small-incision lenticule extraction (SMILE). @*Methods@#From February 2019 to April 2019, 20 patients who underwent LASIK, and 21 who underwent SMILE, were comparedbefore, one day, one week, and one month after surgery. @*Results@#On postoperative day (POD) 1, contrast sensitivity was better in the LASIK group than in the SMILE group under all conditionsfor 1.6, 1, and 0.64 cycles per degree (cpd). One week after surgery, the contrast sensitivity of the LASIK group was betterthan that of the SMILE group under photopic conditions with glare for 1.6, 1, and 0.64 cpd, under photopic conditions withoutglare for 1 and 0.64 cpd, and under all scotopic conditions for 2.5, 1.6, and 0.64 cpd (p< 0.05). There was no significant differencebetween the two groups, except under the scotopic conditions without glare for 0.64 cpd at one month after surgery. In theLASIK group, the contrast sensitivity was best at one week after surgery. The SMILE group showed the poorest contrast sensitivityon POD 1, but this gradually improved. @*Conclusions@#The LASIK group had better contrast sensitivity on one day and one week after surgery than the SMILE group, butthere was no significant difference at one month after surgery. In the LASIK group, the contrast sensitivity was best at one weekafter surgery. In the SMILE group, the contrast sensitivity was worst on POD 1.

Refractive Power Outcomes with an Intraocular Lens with 0.25-diopter Intervals

Purpose@#The Eyelike K-flex Aspheric® (Koryoeyetech, Seoul, Korea) is manufactured in 0.25-diopter (D) intervals, which allows the target refractive error after surgery to be achieved. We here evaluate the refractive power outcomes. @*Methods@#We retrospectively studied 95 eyes of 72 patients who underwent cataract surgery with implantation of the Eyelike K-flex Aspheric®. Refractive error was measured at 1 and 2 months postoperatively (33 eyes of 27 patients) and compared to that of patients fitted with 0.50-D-interval lenses (62 eyes of 49 patients). @*Results@#At 1 month postoperatively, the mean absolute error between the spherical equivalent and planned value was 0.33 ± 0.28 and 0.41 ± 0.39 D in the 0.25- and 0.50 D-interval lens groups, respectively (p = 0.318). At 2 months postoperatively, the respective values were 0.21 ± 0.15 and 0.34 ± 0.29 D (p = 0.009). @*Conclusions@#The Eyelike K-flex Aspheric® shows excellent refractive predictability; use of 0.25-D-interval intraocular lenses close to the target refractive power allows the desired spherical equivalent to be achieved.

Accuracy of Intraocular Lens Power Calculations Based on Total and Standard Keratometry

Purpose@#To compare the accuracy of standard and total keratometry data obtained using the Barrett Universal II and Barrett Toric Calculator. @*Methods@#In total, 111 eyes of 111 patients who visited our hospital for cataract surgery from February 2019 to September 2019 were included in this study. Total keratometry and standard keratometry data were obtained using the Barrett Universal II and the Barrett Toric Calculator; mean absolute errors were derived by using preoperative IOL Master 700® (Carl Zeiss Meditech AG, Jena, Germany) data and 2-month postoperative manifest refraction data. The mean absolute errors of the two methods were compared in terms of a posterior corneal astigmatism greater than 0.3 diopter (D) in patients fitted with Toric intraocular lenses. @*Results@#Using the Barrett Universal II formula, the mean absolute error spherical equivalent difference between total keratometry and standard keratometry was 0.021 ± 0.102 D (p = 0.65) when the Barrett Toric Calculator was used. The mean absolute error differences between the two methods were 0.015 ± 0.121 D for the spherical equivalent (p = 0.80) and 0.005 ± 0.870 D for the cylinder measurement (p = 0.94). In terms of a posterior corneal astigmatism greater than 0.3 D, the mean absolute error spherical equivalent and cylinder measurement differences were -0.020 ± 0.107 D (p = 0.70) and -0.023 ± 0.055 D (p = 0.50) in patients fitted with Toric intraocular lenses. @*Conclusions@#The total keratometry method, which directly measures posterior corneal curvature, yields data comparable to those of the standard keratometry method. When the posterior corneal astigmatism was greater than 0.3 D, we found no significant difference between the total keratometry and standard keratometry data of patients fitted with Toric intraocular lenses.

Refractive Power Outcomes with an Intraocular Lens with 0.25-diopter Intervals

Purpose@#The Eyelike K-flex Aspheric® (Koryoeyetech, Seoul, Korea) is manufactured in 0.25-diopter (D) intervals, which allows the target refractive error after surgery to be achieved. We here evaluate the refractive power outcomes. @*Methods@#We retrospectively studied 95 eyes of 72 patients who underwent cataract surgery with implantation of the Eyelike K-flex Aspheric®. Refractive error was measured at 1 and 2 months postoperatively (33 eyes of 27 patients) and compared to that of patients fitted with 0.50-D-interval lenses (62 eyes of 49 patients). @*Results@#At 1 month postoperatively, the mean absolute error between the spherical equivalent and planned value was 0.33 ± 0.28 and 0.41 ± 0.39 D in the 0.25- and 0.50 D-interval lens groups, respectively (p = 0.318). At 2 months postoperatively, the respective values were 0.21 ± 0.15 and 0.34 ± 0.29 D (p = 0.009). @*Conclusions@#The Eyelike K-flex Aspheric® shows excellent refractive predictability; use of 0.25-D-interval intraocular lenses close to the target refractive power allows the desired spherical equivalent to be achieved.

Accuracy of Intraocular Lens Power Calculations Based on Total and Standard Keratometry

Purpose@#To compare the accuracy of standard and total keratometry data obtained using the Barrett Universal II and Barrett Toric Calculator. @*Methods@#In total, 111 eyes of 111 patients who visited our hospital for cataract surgery from February 2019 to September 2019 were included in this study. Total keratometry and standard keratometry data were obtained using the Barrett Universal II and the Barrett Toric Calculator; mean absolute errors were derived by using preoperative IOL Master 700® (Carl Zeiss Meditech AG, Jena, Germany) data and 2-month postoperative manifest refraction data. The mean absolute errors of the two methods were compared in terms of a posterior corneal astigmatism greater than 0.3 diopter (D) in patients fitted with Toric intraocular lenses. @*Results@#Using the Barrett Universal II formula, the mean absolute error spherical equivalent difference between total keratometry and standard keratometry was 0.021 ± 0.102 D (p = 0.65) when the Barrett Toric Calculator was used. The mean absolute error differences between the two methods were 0.015 ± 0.121 D for the spherical equivalent (p = 0.80) and 0.005 ± 0.870 D for the cylinder measurement (p = 0.94). In terms of a posterior corneal astigmatism greater than 0.3 D, the mean absolute error spherical equivalent and cylinder measurement differences were -0.020 ± 0.107 D (p = 0.70) and -0.023 ± 0.055 D (p = 0.50) in patients fitted with Toric intraocular lenses. @*Conclusions@#The total keratometry method, which directly measures posterior corneal curvature, yields data comparable to those of the standard keratometry method. When the posterior corneal astigmatism was greater than 0.3 D, we found no significant difference between the total keratometry and standard keratometry data of patients fitted with Toric intraocular lenses.

Bilateral Corneal Opacities with Galactokinase Deficiency and Spinal Muscular Atrophy

PURPOSE@#To report a case of bilateral corneal opacities and rare spinal muscular atrophy type III (Kugelberg-Welander disease) in a galactokinase-deficiency patient.CASE SUMMARY: A 6-year-old female presented with bilateral ground glass-like superficial stromal corneal opacities in the corneal center. The patient exhibited developmental motor delay. On muscle biopsy, skeletal muscle neurogenic atrophy consistent with spinal muscular atrophy type III, i.e., Kugelberg-Welander disease, was diagnosed, as well as galactokinase deficiency. On genetic examination, mutation analysis showed an A198V mutation of galactokinase in chromosome 17q24 (“Osaka” variant).@*CONCLUSIONS@#Bilateral corneal opacities and spinal muscular atrophy type III was found in a galactokinase-deficiency patient.

A Case of Clozapine-induced Corneal and Lenticular Pigmentation

PURPOSE: To report a case of corneal and lenticular pigmentation after prolonged clozapine therapy. CASE SUMMARY: A 56-year-old male visited our hospital with a progressive decline in vision that affected both eyes. He had a history of schizophrenia. He was being treated with 200 mg clozapine and 1 mg lorazepam daily, and had been treated with clozapine for 5 years. At the first visit, his best-corrected-visual acuity was 20/32 in both eyes. Slit lamp examination of the corneas showed bright, fine, grayish-brown deposits on the endothelium, and on dilation, bilateral central stellate opacity of the anterior portion of the lens capsule was revealed. CONCLUSIONS: Clozapine may induce corneal and lenticular pigmentation and thus may lead to a decline in vision. Patients on long-term clozapine therapy should be considered for regular ophthalmic review.

Repositioning of a Free Cap after Laser-assisted in situ Keratomileusis

PURPOSE: To report a case of irregular astigmatism caused by a free flap during laser-assisted in situ keratomileusis (LASIK) surgery that was treated with a flap rotation based on postoperative topography. CASE SUMMARY: A 21-year-old female underwent LASIK, which was complicated by a free cap on her right eye. Because the gentian violet markings were no longer present, the exact orientation of the cap was unknown. At 3 months after surgery, the astigmatism of the right eye was −3.00 diopters (D) with an uncorrected visual acuity (UCVA) of 0.4, and the astigmatism of the left eye was −0.75 D with an UCVA of 1.0. The corneal topography was analyzed in order to return to the existing position. Free cap repositioning was performed and irregular astigmatism was corrected to improve the UCVA to 1.0. CONCLUSIONS: If the preoperative markings cannot be identified on a free flap during LASIK, secondary postoperative corneal topographic analysis can be performed to restore the corneal free flap to its original position to minimize astigmatism with good visual outcomes.

A Comparison of Axial Length, Keratometry, and Measured White-to-white Using Different Devices

PURPOSE: To compare the accuracy and clinical usefulness of various devices by measuring axial length, keratometry, and white-to-white. METHODS: In 64 eyes of 56 cataract patients, axial length was measured using Galilei™, Lenstar®, and A-scans, and keratometry was measured using Galilei™, Lenstar®, and ARK. In 86 eyes of 74 cataract patients, white-to-white was measured using Galilei™ and Lenstar®. RESULTS: The average axial length measurements using Galilei™, Lenstar®, and A-scans were significantly correlated (p < 0.001), but without a statistically significant difference (p = 0.611). The 95% agreement range was the smallest at 0.22 mm for the Lenstar® and A-scans. The average mean K using Galilei™, Lenstar®, and ARK were significantly correlated (p < 0.001), but without a statistically significant difference (p = 0.657). The 95% agreement range was relatively small at 1.83 D for Lenstar® and ARK. The average white-to-white using Galilei™ and Lenstar® were significantly correlated (p < 0.001), with a statistically significant difference (p = 0.011). The 95% agreement range was 2.20 mm. CONCLUSIONS: Axial length, keratometry, and white-to-white measured by different devices were highly correlated and were not statistically different; however, agreement was low between measurements. It is therefore important to consider these findings when using them equally.

Comparisons for Evaluation of Efficacy and Safety of Cyclosporin A 0.05% Ophthalmic Emulsion Treatment Groups

PURPOSE: To evaluate and compare the efficacy and safety of cyclosporine 0.05% (Cyporin N eye drops 0.05%) to an active comparator (Restasis®) in moderate to severe dry eye patients. METHODS: This is a multicenter, randomized, double-blind, parallel, active control, non-inferiority, phase III study. Patients had a 2-week run-in period (during the run-in period, patients used artificial tears, if applicable), and afterward 158 patients were randomly assigned treatment for 12 weeks with cyclosporine 0.05% (with artificial tears, if applicable), in which the efficacy and safety were evaluated every four weeks. RESULTS: Corneal staining tests showed that in the per protocol set group, the study group was not inferior to the control group; the results for the full analysis set analytic group were the same. The number of adverse events reported from the 158 patients was not significantly different between groups (p = 0.1107). Additionally, other evaluations, including tolerability evaluations, clinical pathology examinations, and vital signs, show that there is no difference in terms of safety between the groups. CONCLUSIONS: Cyclosporine A 0.05% (Cyporin N eye drops 0.05%) is considered to have the same efficacy and safety compared to the active comparator.

Comparison of Anterior Chamber Depth and Central Corneal Thickness Measured Using Different Devices

PURPOSE: To compare the accuracy and clinical usefulness of different devices by measuring anterior chamber depth (ACD) with three devices and central corneal thickness (CCT) with four devices. METHODS: In 180 eyes of 90 healthy subjects, ACD was measured using A-scan, Lenstar LS900®, Pentacam®, and CCT was measured using ultrasound pachymetry (USP), Lenstar LS900®, Pentacam®, and anterior segment optical coherence tomography (OCT). RESULTS: The average ACT measurements using Lenstar LS900®, A-scan, and Pentacam® were 3.27 ± 0.35 mm, 3.26 ± 0.36 mm, and 3.25 ± 0.36 mm, respectively. The measurements were significantly correlated (p < 0.001) but without statistically significant difference (p = 0.017). The Bland-Altman plots showed a low degree of agreement. The average CCT measurements using Pentacam®, USP, Lenstar LS900®, and OCT were 553.31 ± 25.23 µm, 547.26 ± 23.83 µm, 541.38 ± 24.49 µm, and 531.40 ± 22.33 µm, respectively. The measurements were significantly correlated (p < 0.001) and statistically significantly different (p < 0.05). The Bland-Altman plots showed a low degree of agreement. CONCLUSIONS: ACD and CCT measured using different devices were highly correlated, but the ACD measurements were not statistically different; however, the CCT measurements were statistically different, and agreement was low between both measurements.

Tear Meniscus Evaluation Using Optical Coherence Tomography in Dry Eye Patients

PURPOSE: To evaluate the tear meniscus in aqueous tear-deficient dry eye patients using Fourier-domain optical coherence tomography (FD-OCT) and to investigate the clinical usefulness of tear meniscus values. METHODS: The present study included 79 aqueous tear-deficient dry eyes and 50 normal eyes. Tear meniscus height (TMH), tear meniscus depth (TMD), and tear meniscus area (TMA) were imaged using FD-OCT and measured with computer calipers. Schirmer's test, tear break-up time, and corneal fluorescein staining were also performed and the correlations between the tests were analyzed. Additionally, the diagnostic power of tear meniscus values was compared using area under the receiver operating characteristic curve (AUROC). RESULTS: Tear meniscus values were significantly decreased in the aqueous tear-deficient dry eye group (p < 0.05). TMH, TMD, and TMA were positively correlated with Schirmer's test and tear break-up time (p < 0.05), and TMH and TMD were negatively correlated with corneal fluorescein staining in the aqueous tear-deficient dry eye group (p < 0.05). The AUROCs of TMH, TMD, and TMA were 0.978, 0.788, and 0.957, respectively. CONCLUSIONS: Tear meniscus values measured using FD-OCT were significantly lower in aqueous tear-deficient dry eyes and were correlated with Schirmer's test, tear break-up time, and corneal fluorescein staining. Tear meniscus measurements obtained using FD-OCT can be useful clinical parameters for the diagnosis and treatment of aqueous tear-deficient dry eye.

Tear Meniscus Evaluation Using Optical Coherence Tomography in Meibomein Gland Dysfunction Patients

PURPOSE: This study compared tear meniscus parameters between normal control, aqueous tear deficient dry eye, and meibomein gland dysfunction groups using Fourier-domain optical coherence tomography (FD-OCT). METHODS: This study included 33 normal eyes, 79 aqueous tear-deficient dry eyes (ATD), and 48 meibomein gland dysfunction dry eyes (MGD). Following routine examination including Schirmer test, tear break-up time, corneal staining, and tear meniscus parameters such as tear meniscus height (TMH), tear meniscus depth (TMD), and tear meniscus area (TMA) were obtained using FD-OCT. The differences among groups were assessed. RESULTS: The averages of TMH, TMD, and TMA were 295.58 +/- 58.36 microm, 166.67 +/- 30.43 microm, and 0.0360 +/- 0.01100 mm2 in normal eyes, respectively, 226.43 +/- 42.18 microm, 147.44 +/- 38.38 microm, and 0.0209 +/- 0.01015 mm2 in ATD, respectively, 272.81 +/- 64.21 microm, 159.37 +/- 44.05 microm, and 0.0295 +/- 0.01271 mm2 in MGD, respectively. Tear meniscus parameters were significantly lower in ATD. Tear meniscus parameters in MGD were higher than ATD and lower than normal eyes, but the TMA was the only statistically significant value. CONCLUSIONS: Although tear meniscus parameters in MGD were higher than ATD, they could not be distinguished from normal eyes. Tear meniscus evaluation using FD-OCT could be a useful measurement system in classification and treatment choice for dry eye patients.

Comparison of Biometric Measurements and Refractive Results between Applanation Ultrasonography and Three Different Interferometries

PURPOSE: To compare ocular biometry and refractive results measured using conventional applanation ultrasonography and 3 different optical interferometries, Lenstar LS900(R), AL-Scan(R) and OA-2000(R). METHODS: The biometries of 31 cataractous eyes were measured using ultrasonography, Lenstar LS900(R), AL-Scan(R) or OA-2000(R). The axial length, anterior chamber depth and keratometry were measured. The SRK/T formula was used to calculate intraocular lens power. Two months after cataract surgery, the refractive outcome was determined and results from the 4 different biometry methods were compared. RESULTS: Axial lengths were 23.39 +/- 0.95 mm, 23.42 +/- 0.98 mm, 23.43 +/- 0.98 mm and 23.44 +/- 0.98 mm measured using ultrasonography, Lenstar LS900(R), AL-Scan(R) and OA-2000(R), respectively with no statistically significant differences observed (p = 0.996). The anterior chamber depth and keratometry were 3.14 +/- 0.41 mm, 3.10 +/- 0.38 mm and 3.13 +/- 0.39 mm (p = 0.936) and 44.41 +/- 1.52 D, 44.54 +/- 1.57 D and 44.44 +/- 1.52 D (p = 0.937) for Lenstar LS900(R), AL-Scan(R) and OA-2000(R) respectively. There were no statistically significant differences between the 3 optical devices. The mean absolute error of the 4 different devices were not statistically significant (p = 0.722). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using ultrasonography, Lenstar LS900(R), AL-Scan(R) or OA-2000(R) showed no significant differences.